Natural radioactivity and indoor radiation measurements in buildings and building materials in Gobichettipalayam town

Samples of natural and manufactured building materials used by the people of Gobichettipalayam town have been analyzed for Ra-226, Th-232 and K-40 using gamma-ray spectrometry. Radium equivalent activity of the materials has been measured using the formula given by OECD and the geometric mean value of sand, clay and cements are found to be 53.53 Bq center dot kg(-1), 89.09 Bq center dot kg(-1) and 72.25 Bq center dot kg(-1), respectively. The radium equivalent activities obtained in the building materials are all well below the acceptable limit. The indoor gamma-dose has been measured using thermoluminescence dosimeters and it was found in the range of 1051.2-3946.0 mu Gy/year. The annual effective indoor gamma radiation dose to the people of Gobichettipalayam town has been found to be 0.8 mSv/y.